Plastic article or earthenware shaping or treating: apparatus – With apparatus assembly or dismantling means or with idle part – For press shaping surface
Reexamination Certificate
1998-11-24
2001-04-03
Pyon, Harold (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With apparatus assembly or dismantling means or with idle part
For press shaping surface
C425S335000, C425S363000, C425S367000
Reexamination Certificate
active
06210145
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims priority to German Patent Application 197 52 524.5 filed Nov. 27, 1997, which is herein expressly incorporated by reference.
BACKGROUND OF THE INVENTION
The invention relates to a calender for a thermoplastic material sheets extruded by an extrusion die via a sheet die.
U.S. Pat. No. 4,997,358 discloses a calender in which more than one roll is provided to smooth and cool the sheet of molten thermoplastic material extruded via the sheet die. The rolls are arranged on a frame. The plastic which is processed to a sheet needs an adaption of the guidance and of the dwell time of the material sheet in contact with the rolls to achieve the required thickness tolerance and required surface of the material sheet. Because of this at least one stationary roll and one adjustable roll, which can be set to different angular settings around the stationary roll, are provided. The adjustable roll is held in guide frames with its ends rotatable and radially adjustable to the stationary roll. The frames can be fixed on both sides of the stationary roll. The frames have discs with circumferentially distributed holes which receive bolts to secure the rolls internal ends. The radial external ends of the frames are attachable to carrier arms of the basic frame by bolts. As the discs act upon the bearings beddings of the stationary roll, they are further loaded. Furthermore, the accessibility of the adjustable roll as well as of the stationary roll is decreased.
SUMMARY OF THE INVENTION
The subject of the invention is to create a calender which stands out through a good handling and which enables the maintenance of tight tolerances for the processed material sheet.
To solve this problem, the calender includes a frame, with rolls for smoothing and cooling the material sheet. The rolls are provided at the frame. One roll is stationary and at least one is designed as an adjustable roll. The adjustable roll is arranged adjustable around and radially adjustable to the stationary roll.
Each adjustable roll is held rotatable at both its ends in bearings. Each of the two bearings is radially adjustably arranged on a guide car about the axis of rotation of the stationary roll. The guide cards of each adjustable roll arc supported on guide rails. The guide rails are separated from the bearing of the stationary roll. The guide rails are arranged at a distance from the stationary roll and have guideways for the guide cars. The guideways extend circularly around the axis of rotation of the stationary roll. Each adjustable roll is stepless circumferentially adjustable by means of the guide cars on the guide rails around the stationary roll. The guide rails are connected to the frame or form a part of it.
A good handling of the unit and a high rigidity for the support of the adjustable roll is arrived at by the separation of the support and of the guidance of each adjustable roll from the bearing (bedding) of the stationary rolls. Because of this, the bearings of the stationary roll stay uninfluenced. This also means that no forces are applied to the stationary roll by an additional support of the adjustable roll. Accordingly, this achieves high adjustment precision and maintenance of a tight toleranced gap between the stationary roll and the adjustable roll. Furthermore, the displacement, pivoting, of the adjustable roll around the stationary roll is also increased compared with a solution where the adjustable roll is fixed at the stationary roll. Thus, a very rigid bearing and support for the adjustable roll is achieved.
The characteristics of the different plastic materials make it desirable to adjust the intake of the hot material sheet exiting the sheet die to the rolls of the calender. There are materials which require an inclined or a straight downwardly directed exiting position of the sheet die. The exiting material sheet is subjected to high tensile stresses at a horizontal intake into the calender. Other materials require horizontal intake.
In the further development of the solution according to the invention, the frame together with the guide rails is pivotable around a swivel axis which runs parallel to the axis of rotation of the stationary roll. The circular running guide rails offer themselves for pivoting. These can be used for carrying out a pivoting adjustment. Thus, pivoting takes place via the periphery of the guide rails. Matching feeding ratios can be achieved by the pivotable arrangement where a laminating plastic sheet or a reinforcement sheet is fed. The swivel axis is preferably arranged such that it is identical to the axis of rotation of the stationary roll.
In the concretization of the adjustment of the adjustable roll at both ends of the adjustable roll, two guide rails forming a pair are arranged parallel to each other. One guide car is received between each pair. Each guide car has rollers which support it on inner and outer guideways of the guide rails. The narrow face of one guide rail of each pair of guide rails has teeth which engage a toothed pinion mounted on the attached guide car.
To achieve synchronization of the two guide cars for an exact parallel adjustment of the ends of the adjustable roll, the two pinions of the guide cars arranged at both ends of the adjustable roll are connected to each other by a shaft. One pinion is drivable by a power drive.
Finally, an arrangement is chosen where guide rails are arranged externally in the longitudinal direction of the adjustable roll. The rails have teeth on their radial outer narrow faces. The bearing of the frame to pivot around the axis of rotation of the stationary roll takes place in a further embodiment of the invention. The radially external narrow faces of the untoothed guide rails are carried by rollers mounted on a carrier frame. Two driving pinions are supported in bearings in the carrier frame to pivot the frame. The drive pinions both engage teeth on the radially external narrow face of the two teeth guide bars. Both pinions are driven by a joint drive unit so that synchronized pivoting takes place. The rollers which carry one of the untoothed guide rails are provided with rims for the side support towards the carrier frame. The rims embrace the sides of the associated guide rails. The other rollers which are assigned to the further untoothed guide rail are cylindrical. Jamming can be avoided by such an embodiment.
The calender preferably comprises three rolls. One of these represents the stationary and one the adjustable roll. The third roll is arranged in the frame and is only radially adjustable to the stationary roll. However, the third roll can also be designed and arranged as an adjustable roll.
Preferably, the carrier frame is height adjustable. This enables orientations towards the extruder in an even more flexible manner. Furthermore, the carrier frame can also be provided with runners which, for example, run on rails. A height adjustable arrangement of the runners on the carrier frame is advantageous.
From the following detailed description, taken in conjunction with the drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.
REFERENCES:
patent: 2971218 (1961-02-01), Bierer
patent: 4997358 (1991-03-01), Perkins et al.
patent: 5558017 (1996-09-01), Berger et al.
patent: 5-98591 (1993-04-01), None
Harness & Dickey & Pierce P.L.C.
Heckenberg Donald
Pyon Harold
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